This is an application for a Midcareer Award for Patient-Oriented Research (K24) for Lee H. Harrison, M.D., Associate Professor of Medicine, Epidemiology, and Infectious Diseases and Microbiology at the University of Pittsburgh School of Medicine and Graduate School of Public Health. The goal of this application is to allow the candidate to substantially change the direction of his career, with an increased emphasis on mentoring junior faculty, doctoral students, and infectious diseases fellows interested in pursuing careers in patient-oriented research. Specifically, this K24 award will allow Dr. Harrison to: 1) provide mentoring in patient-oriented research to infectious diseases fellows and junior faculty in the School of Medicine, doctoral students in the Graduate School of Public Health, and junior investigators from Brazil, 2) in collaboration with a junior faculty member mentored by the candidate, conduct a study to identify factors for persistent shedding of HIV RNA in semen among HIV-infected persons taking highly-active antiretroviral therapy, 3) build the research of the Infectious Diseases Epidemiology Research Unit, which the candidate recently established at the University of Pittsburgh. The focus of the unit is the epidemiology and prevention of HIV infection in Brazil and the epidemiology, molecular epidemiology, and prevention of vaccine-preventable and drug-resistant invasive bacterial infections. The candidate has a successful track record of publication and mentoring in both of these areas of research. This award will allow Dr. Harrison to substantially change his day-to-day role on a variety of research projects he directs. The increase in protected time will lead to an increase in research productivity particularly because it will provide protected time for mentoring the next generation of patient-oriented investigators at the University of Pittsburgh.